problem1 link 暴力搜索即可. problem2 link 可以将每次所有的piece的位置看作一个状态,由于$C_{25}^{5}=53130$,所以最多有这么多状态.这里可以加一些优化来减少状态.比如通过旋转或者翻转是一样的状态其结果是一样的. 然后进行bfs即可. problem3 link 对于一个状态$mask$来说,可以将其分成两个子状态$S_{1},S_{2}=mask-S_{1}$.为了防止重复,可以令两个固定的点$u_{1} \in S_{1},v_{1} \in…
problem1 link 倒着想.每次添加一个右括号再添加一个左括号,直到还原.那么每次的右括号的选择范围为当前左括号后面的右括号减去后面已经使用的右括号. problem2 link 令$h(x)=\sum_{i=1}^{x}g(i)$,那么答案为$h(R)-h(L-1)$.对于$h(x)$: (1)如果$x\leq K$,那么$h(x)=0$ (2)否则对于$[K+1,x]$之间的所有偶数来说,对答案的贡献为$even+h(\frac{x}{2})-h(\frac{K}{2})$,其中$e…
Problem Statement You are given the ints perimeter and area. Your task is to find a triangle with the following properties: The coordinates of each vertex are integers between 0 and 3000, inclusive. The perimeter of the triangle must be exactly…
Problem Statement The Happy Letter game is played as follows: At the beginning, several players enter the field. Each player has a lowercase English letter on their back. The game is played in turns. In each turn, you select two players with dif…
